'use strict'
const path = require('path')
const CompressionPlugin = require("compression-webpack-plugin")

function resolve(dir) {
	return path.join(__dirname, dir)
}

// If your port is set to 80,
// use administrator privileges to execute the command line.
// For example, Mac: sudo npm run
// You can change the port by the following method:
// port = 9528 npm run dev OR npm run dev --port = 9528
const port = process.env.port || process.env.npm_config_port || 7878 // dev port

// All configuration item explanations can be find in https://cli.vuejs.org/config/
module.exports = {
	/**
	 * You will need to set publicPath if you plan to deploy your site under a sub path,
	 * for example GitHub Pages. If you plan to deploy your site to https://foo.github.io/bar/,
	 * then publicPath should be set to "/bar/".
	 * In most cases please use '/' !!!
	 * Detail: https://cli.vuejs.org/config/#publicpath
	 */
	publicPath: './',
	outputDir: 'dist',
	assetsDir: 'static',
	lintOnSave: process.env.NODE_ENV === 'development',
	productionSourceMap: false,
	parallel: false,
	runtimeCompiler: true,
	devServer: {
		port: port,
		open: true,
		overlay: {
			warnings: false,
			errors: true
		}
	},
	configureWebpack: {
		// provide the app's title in webpack's name field, so that
		// it can be accessed in index.html to inject the correct title.
		name: '',
		resolve: {
			alias: {
				'@': resolve('src')
			}
		},
		performance: {
			hints: 'warning',
			//入口起点的最大体积 整数类型（以字节为单位）
			maxEntrypointSize: 50000000,
			//生成文件的最大体积 整数类型（以字节为单位 300k）
			maxAssetSize: 50000000,
			//只给出 js 文件的性能提示
			assetFilter: function(assetFilename) {
				return assetFilename.endsWith('.js');
			}
		},
		plugins: [
			new CompressionPlugin({
				test: /\.(js|css)(\?.*)?$/i, //需要压缩的文件正则
				threshold: 10240, //文件大小大于这个值时启用压缩
				deleteOriginalAssets: false //压缩后保留原文件
			})
		]
	},
	chainWebpack(config) {
		// config.plugin('html').tap(args => {
		// 	args[0].title = ''
		// 	return args
		// })

		config.plugins.delete('preload') // TODO: need test
		config.plugins.delete('prefetch') // TODO: need test

		// set preserveWhitespace
		config.module
			.rule('vue')
			.use('vue-loader')
			.loader('vue-loader')
			.tap(options => {
				options.compilerOptions.preserveWhitespace = true
				return options
			})
			.end()

		config
			// https://webpack.js.org/configuration/devtool/#development
			.when(process.env.NODE_ENV === 'development',
				config => config.devtool('cheap-source-map')
			)

		config
			.when(process.env.NODE_ENV !== 'development',
				config => {
					config
						.plugin('ScriptExtHtmlWebpackPlugin')
						.after('html')
						.use('script-ext-html-webpack-plugin', [{
							// `runtime` must same as runtimeChunk name. default is `runtime`
							inline: /runtime\..*\.js$/
						}])
						.end()
					config
						.optimization.splitChunks({
							chunks: 'all',
							cacheGroups: {
								libs: {
									name: 'chunk-libs',
									test: /[\\/]node_modules[\\/]/,
									priority: 10,
									chunks: 'initial' // only package third parties that are initially dependent
								},
								elementUI: {
									name: 'chunk-elementUI', // split elementUI into a single package
									priority: 20, // the weight needs to be larger than libs and app or it will be packaged into libs or app
									test: /[\\/]node_modules[\\/]_?element-ui(.*)/ // in order to adapt to cnpm
								},
								commons: {
									name: 'chunk-commons',
									test: resolve('src/components'), // can customize your rules
									minChunks: 3, //  minimum common number
									priority: 5,
									reuseExistingChunk: true
								}
							}
						})
					config.optimization.runtimeChunk('single')
				}
			)
	}
}
